The present invention relates to a lithium-sulphur cell comprising a laminate that is folded in a zigzag configuration.
A typical lithium-sulphur cell comprises an anode (negative electrode) formed from lithium metal or a lithium metal alloy and a cathode (positive electrode) formed from elemental sulphur or other electroactive sulphur material. The sulphur or other electroactive sulphur-containing material may be mixed with an electrically conductive material, such as carbon, to improve its electrical conductivity. Typically, the carbon and sulphur are ground and then mixed with a solvent and binder to form a slurry. The slurry is applied to a current collector and then dried to remove the solvent. The resulting structure is calendared to form a composite sheet of cathodic material deposited on a current collector, which is cut into the desired shape to form a cathode. Electrolyte is applied to the cathode. A separator is then placed over the cathode and a lithium anode placed over the separator.
To date, lithium-sulphur cells have been produced by a batch process comprising a number of time-consuming steps. For example, the composite sheets of cathodic material and sheets of lithium metal or lithium metal alloy have to be cut to a desired shape prior to cell assembly. In particular, the sheets have to be cut in such a way so as to provide protruding portions or tabs to which contact leads may be welded. This can add to the complexity of the overall process. Moreover, in known methods of cell assembly, individual, pre-cut individual sheets of cathode, separator and anode are placed over one another in a batch process. Such processes can be difficult to automate.
The present inventors have designed a lithium-sulphur cell that can be assembled in an efficient and effective manner. The present inventors have also developed an efficient and effective process for manufacturing a lithium-sulphur cell.